Silicone hydrogel contact lenses

ABSTRACT

Silicone hydrogel contact lenses are formed from the reaction product of a polymerizable composition comprising at least one acrylate-containing siloxane monomer, at least one hydrophilic vinyl-containing monomer, and at least one vinyl-containing cross-linking agent. The contact lenses have ophthalmically-acceptable ionoflux values and surface wettability, and can be manufactured without the use of volatile organic solvents.

This application is a National Stage Application of PCT/US2012/026220,filed Feb. 23, 2012, and which claims the benefit under 35 U.S.C.§119(e) of prior U.S. Provisional Patent Application No. 61/447,193,filed Feb. 28, 2011, which is incorporated in its entirety by referenceherein.

FIELD

The field of the invention relates to silicone hydrogel contact lenses.

BACKGROUND

Contact lenses made from silicone hydrogels are rapidly gainingpopularity over contact lenses made from conventional hydrogel materialsbecause, like conventional hydrogel lenses, they are comfortable towear, but they have the added advantage of having higher oxygenpermeability, which is believed to be healthier for the eye. However,contact lenses made from silicone hydrogels often have physicalproperties that make them more difficult to process duringmanufacturing, and typically the lenses need to be extracted in volatileorganic solvents to achieve acceptable surface wettability and gooddimensional stability. The use of volatile organic solvents inmanufacturing presents safety and environmental concerns and adds coststo the manufacturing process.

New formulations of silicone hydrogel contact lenses that can bemanufactured without the use of volatile organic solvents, and thatresult in dimensionally stable contact lenses havingophthalmically-acceptable surface wettabilities are desired.

Some patent documents describing silicone hydrogel contact lensesinclude U.S. Publ. No. 2007/0296914, U.S. Publ. No. 2007/0066706, U.S.Publ. No. 2007/0231292, U.S. Pat. No. 5,965,631, WO 2011/041523, U.S.Pat. No. 5,358,995, European Publ. No. 1870736A1, U.S. Publ. No.2006/063852, U.S. Publ. No. 2011/0009587, and U.S. Publ. No.2009/0234087.

SUMMARY

We have made improved silicone hydrogel contact lenses havingophthalmically acceptably wettable lens surfaces that can bemanufactured without the use of volatile organic solvents. The contactlenses are prepared from a polymerizable composition comprising at leastone acrylate-containing siloxane monomer, at least one hydrophilicvinyl-containing monomer, and at least one vinyl-containingcross-linking agent.

The present disclosure is directed to a silicone hydrogel contact lenscomprising a polymeric lens body that is a reaction product of apolymerizable composition comprising at least one acrylate-containingsiloxane monomer; at least one hydrophilic vinyl-containing monomer; andat least one vinyl-containing cross-linking agent, wherein the contactlens has an ionoflux of less than 10×10⁻³ mm²/min. In one example, thepolymerizable composition has a total amount of acrylate-containingsiloxane monomer of from about 2 mol. % to about 15 mol. %. In oneexample, the polymerizable composition has a total amount of hydrophilicvinyl-containing monomer of from about 50 mol. % to about 85 mol. %. Inone example, the polymerizable composition has a total amountvinyl-containing cross-linking agent of from about 0.02 mol. % to about0.20 mol. %. In a further example, the polymerizable composition has amolar ratio of total amount of hydrophilic vinyl-containing monomer tototal amount of acrylate-containing siloxane monomer of from 5:1 to30:1, respectively.

In one example, the hydrophilic vinyl-containing monomer can be selectedfrom N-vinyl-N-methyl acetamide (VMA), or N-vinyl pyrrolidone (NVP), or1,4-butanediol vinyl ether (BVE), or ethylene glycol vinyl ether (EGVE),or diethylene glycol vinyl ether (DEGVE), or any combination thereof. Ina specific example, the hydrophilic vinyl-containing monomer comprises afirst hydrophilic vinyl-containing monomer and a second hydrophilicvinyl-containing monomer having a polymerizable group that is differentfrom that of the first hydrophilic monomer. In one such example, thefirst hydrophilic monomer can comprise or consist of a vinylamide-containing monomer and the second hydrophilic monomer can compriseor consist of a vinyl ether-containing monomer.

In one example, the vinyl-containing cross-linking agent can be selectedfrom divinyl ether, or divinyl sulfone, or triallyl phthalate, ortriallyl isocyanurate, or diallyl phthalate, or diethyleneglycol divinylether, or triethyleneglycol divinyl ether, or any combination thereof.

In one example, the acrylate-containing siloxane monomer can comprises acombination of a mono-functional acrylate-containing siloxane monomerand a bi-functional acrylate-containing siloxane monomer. In a furtherexample, the mono-functional acrylate-containing siloxane monomer has amolecular weight of less than 2,000, and the bi-functionalacrylate-containing siloxane monomer has a molecular weight of at least3,000. In yet a further example, the mono-functional acrylate-containingsiloxane monomer and the bi-functional acrylate-containing siloxanemonomer are present in the polymerizable composition at a molar ratio ofat least 30:1, respectively.

Another aspect of the present disclosure is a method of manufacturing asilicone hydrogel contact lens, said method comprising a) preparing apolymerizable composition comprising at least one acrylate-containingsiloxane monomer, at least one hydrophilic vinyl-containing monomer, andat least one vinyl-containing cross-linking agent; b) polymerizing thepolymerizable composition to form a polymeric lens body; and c)contacting the polymeric lens body with a washing liquid to removeunreacted or partially reacted components from the polymeric lens body,wherein the washing liquid and any other liquid used for washing thepolymeric lens body are substantially free of volatile organic solvents.In a specific example, the polymerizable composition is polymerized in amold having non-polar molding surfaces.

DETAILED DESCRIPTION

Silicone hydrogel contact lenses are described herein that can bemanufactured without the use of volatile organic solvents. The contactlenses have good manufacturing processability, are dimensionally stable,and have ophthalmically-acceptable ionoflux and surface wettability. Thesilicone hydrogel contact lens comprises a polymeric lens body that isthe reaction product of a polymerizable composition comprising at leastone acrylate-containing siloxane monomer, at least one hydrophilicvinyl-containing monomer, and at least one vinyl-containingcross-linking agent.

The following definitions for the quoted terms provided below areapplicable herein unless context indicates otherwise:

A “monomer” refers to any molecule capable of reacting with othermolecules that are the same or different, to form a polymer orcopolymer. Thus, the term encompasses polymerizable pre-polymers andmacromers, there being no size-constraint of the monomer unlessindicated otherwise.

A “siloxane monomer” contains at least one Si-O group, and is typicallyeither “mono-functional” or “multi-functional”, meaning that it haseither one polymerizable group or two or more polymerizable groups,respectively. A “non-siloxane monomer” is a monomer that does notcontain any Si-O groups.

An “acrylate-containing monomer” is any non-siloxane monomer that has asingle polymerizable acrylate group (e.g. methyl methacrylate,acrylamide, etc.). A siloxane monomer having at least one polymerizableacrylate group is referred to herein as an “acrylate-containing siloxanemonomer”.

A “vinyl-containing monomer” is any non-siloxane monomer that has asingle polymerizable carbon-carbon double bond (i.e., a vinyl group)present in its molecular structure, where the carbon-carbon double bondof the vinyl group is less reactive than the carbon-carbon double bondpresent in an acrylate or a methacrylate polymerizable group under freeradical polymerization. Thus, while a carbon-carbon double bond ispresent in acrylate groups and methacrylate groups, as used herein,monomers comprising a single acrylate or methacrylate polymerizablegroup are not considered to be vinyl-containing monomers.

A monomer is considered “hydrophilic” if at least 50 grams of themonomer are fully soluble in 1 liter of water at 20° C. (i.e., ≧5%soluble in water) as determined visibly using a standard shake flaskmethod.

A “cross-linking agent” is any compound having a molecular weight ofless than about 2,000 with two or more ethylenically unsaturated groups.Thus, a cross-linking agent can react with functional groups on two ormore polymer chains so as to bridge one polymer to another. An“acrylate-containing cross-linking agent” has at least two polymerizableacrylate functional groups, and no other type of polymerizablefunctional group. A “vinyl-containing cross-linking agent” has at leasttwo polymerizable vinyl groups (as defined above), and no other type ofpolymerizable functional group.

A “polymerizable composition” is a composition comprising polymerizableingredients, where the composition has not yet been subjected toconditions that result in polymerization of the polymerizableingredients.

We have discovered that the inclusion of at least one vinyl-containingcross-linking agent in a polymerizable composition comprising at leastone acrylate-containing siloxane monomer and at least one non-siloxanevinyl-containing monomer can be polymerized to provide a polymeric lensbody that can be processed without volatile organic solvents and resultin contact lenses that have ophthalmically-acceptable ionoflux andsurface wettability. References herein to ‘at least one’ of a type ofingredient refer to both a) a single ingredient, and b) a combination oftwo or more ingredients of the same type.

In one example, the polymerizable composition has a total amount ofacrylate-containing siloxane monomer of from about 2, 3, 4, 5, or 6molar percent (mol. %) up to about 8, 10, 12, 15, 18, or 20 mol. %; atotal amount of hydrophilic vinyl-containing monomer of from about 50,55, 60 or 65 mol. % up to about 75, 80, or 85 mol. %; and a total amountof vinyl-containing cross-linking agent of from about 0.02, 0.04, or0.06 mol. % up to about 0.10, 0.15 or 0.20 mol. %, where molar percentvalues are based upon total moles of reactive ingredients in thepolymerizable composition, with non-reactive ingredients, such asdiluents and other non-reactive components, being excluded from thecalculation. References herein to ‘a total amount’ of a particularcomponent (i.e. a combination of two or more ingredients of the sametype) in a polymerizable composition refer to the sum of the amounts ofall ingredients of the same type. Further, throughout this disclosure,when a series of values is presented with a qualifier preceding thefirst value, the qualifier is intended to implicitly precede each valuein the series unless context indicates otherwise. For example, in theabove listing of molar percent ranges for the total amount ofacrylate-containing siloxane monomer, it is intended that the qualifier“from about” implicitly precedes the values of 2, 3, 4, 5, and 6; andthe qualifier “up to about” implicitly precedes the values of 8, 10, 12,15, 18, and 20. Also, throughout this disclosure, when a series ofvalues is presented with a unit of measurement following the last valueof the series, the unit of measurement is intended to implicitly followeach preceding value in the series unless context indicates otherwise.For example, in the above listing of molar percent ranges for the totalamount of acrylate-containing siloxane monomer, it is intended that theunit of measurement “mol. %” implicitly follows the values of 2, 3, 4,5, 8, 10, 12, 15, and 18. Also, when a series of lower limit ranges anda series of upper limit ranges are provided, all combinations of theprovided ranges are contemplated as if each combination werespecifically listed. For example, in the above listing of molar percentranges for the total amount of acrylate-containing siloxane monomer, all30 possible molar percent ranges are contemplated (i.e. from 2 to 8 mol.%, from 2 to 10 mol. %, from 2 to 15 mol. % . . . from 6 to 15 mol. %,from 6 to 18 mol. %, and from 6 to 20 mol. %). Also, throughout thisdisclosure a reference to “an example” or “a specific example” orsimilar phrase, is intended to introduce a feature or features of thecontact lens, polymerizable composition, or method of manufacture(depending on context) that can be combined with any combination ofpreviously-described or subsequently-described examples (i.e. features),unless a particular combination of features is mutually exclusive, or ifcontext indicates otherwise.

Examples of vinyl-containing cross-linking agents that can be used inthe polymerizable compositions disclosed herein include, withoutlimitation, divinyl ethers, or divinyl sulfones, or triallylisocyanurates, and any combination thereof. Exemplary divinyl ethersinclude diethyleneglycol divinyl ether, or triethyleneglycol divinyl, or1,4-butanediol divinyl ether, or 1,4-cyclohexanedimethanol divinylether, or any combination thereof. Other cross-linking agents suitablefor use in silicone hydrogel polymerizable compositions are known in thefield (see e.g. the patent publications listed in the Backgroundsection). Typically, the vinyl-containing cross-linking agent can havetwo or three polymerizable vinyl groups. The vinyl-containingcross-linking agents, as well as the acrylate-containing cross-linkingagents described further below, typically can have a molecular weight ofless than 1500, 1000, 500, or 250, wherein the molecular weight unitsare given in Daltons, here and throughout this disclosure. In a specificexample, the polymerizable composition has a ratio of polymerizablevinyl groups from the total amount of hydrophilic vinyl-containingmonomer (i.e. one polymerizable vinyl group per molecule) topolymerizable vinyl groups from the total amount of vinyl-containingcross-linking agent (i.e. at least two polymerizable vinyl groups permolecule) of about 50:1, or 100:1 or 200:1 up to about 800:1, or 1000:1,or 1200:1.

Examples of hydrophilic vinyl-containing monomers that can be used inthe polymerizable formulations described herein include hydrophilicmonomers having a single vinyl ether, or vinyl ester, or allyl ester, orvinyl amide polymerizable group. Exemplary hydrophilic vinyl-containingmonomers include N-vinyl-N-methyl acetamide (VMA), N-vinyl pyrrolidone(NVP), 1,4-butanediol vinyl ether (BVE), ethylene glycol vinyl ether(EGVE), diethylene glycol vinyl ether (DEGVE), and combinations thereof.Other suitable hydrophilic vinyl-containing monomers that can be used inthe polymerizable compositions are described, for example, in the patentpublications referenced in the Background section above, which areincorporated herein by reference in their entireties.

In a specific example, the at least one hydrophilic vinyl-containingmonomer can comprise or consist of a first hydrophilic vinyl-containingmonomer and a second hydrophilic vinyl-containing monomer having apolymerizable functional group that is different from that of the firsthydrophilic monomer. In one example, this can increase wettability ofthe contact lens compared to a formulation that comprises a singlehydrophilic vinyl-containing monomer, but is otherwise identical. In onesuch example, the first hydrophilic monomer can be a “vinylamide-containing monomer”, which, as used herein, refers to a monomerthat contains an N-vinyl polymerizable group, and no other polymerizablegroup, where N designates nitrogen. The second hydrophilic monomer canbe a “vinyl ether-containing monomer”, which, as used herein, refers toa monomer that contains an O-vinyl polymerizable group, and no otherpolymerizable group, where O designates oxygen. For example, the firsthydrophilic monomer can be selected from N-vinyl-N-methyl acetamide(VMA) or N-vinyl pyrrolidone (NVP), or N-vinyl formamide, or N-vinylacetamide, or N-vinyl-N-ethyl acetamide, or N-vinyl isopropylamide, orN-vinyl caprolactam, or N-vinyl-N-ethyl formamide, or any combinationthereof; and the second hydrophilic monomer can be selected from1,4-butanediol vinyl ether (BVE), or ethylene glycol vinyl ether (EGVE),or diethylene glycol vinyl ether (DEGVE), or 1,4-cyclohexanedimethanolvinyl ether (CHDMVE), or a poly(ethylene glycol) vinyl ether having from4 to 10 ethylene glycol units, or a poly(ethylene glycol) vinyl etherhaving more than 10 ethylene glycol units, or any combination thereof.In such an example, the polymerizable composition can have a molar ratioof the total amount of vinyl amide-containing monomer to the totalamount of vinyl ether-containing monomer of from about 2:1, 3:1, 4:1, or5:1 up to about 15:1, 20:1, 25:1, or 30:1 respectively. Additionally,the polymerizable composition can comprise from about 50, 55, or 60 mol.% to about 70, 75, 80, or 85 mol. % of the vinyl amide-containingmonomer, and from about 2, 4, or 6 mol. % to about 10, 15, 20, or 25mol. % of the vinyl ether-containing monomer.

In various examples where more than one hydrophilic vinyl-containingmonomer is included in the polymerizable composition, at least 50%, 60%,70% or 80% by weight of the hydrophilic vinyl-containing monomer has asolubility in water of ≧10%, 15% or 20%. In a specific example, 100% ofthe hydrophilic vinyl-containing monomer in the polymerizablecomposition has a solubility in water of ≧10%, 15%, or 20%. Thehydrophilic vinyl-containing monomer typically has a molecular weight ofabout 75 to about 500, and more typically about 75 to 250.

Acrylate-containing siloxane monomers that can be used in thepolymerizable compositions described herein are well-known in the field,such as those referenced in the patent publications cited in theBackground section above. The acrylate-containing siloxane monomer maybe mono-functional, bi-functional, or comprise a combination of mono-and bi-functional acrylate-containing siloxane monomers. In exampleswhere the acrylate-containing siloxane monomer consists of one or moremono-functional acrylate-containing siloxane monomers (i.e. it does notcontain any multi-functional acrylate-containing siloxane monomers), thepolymerizable composition will typically further comprise anacrylate-containing cross-linking agent, described further below. In aspecific example, the acrylate-containing siloxane monomer has one ormore polymerizable methacrylate groups. Various non-limiting examples ofsuitable acrylate-containing siloxane monomers include3-[tris(trimethylsiloxy)silyl]propyl methacrylate (“TRIS”),3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane(“SiGMA”), methyldi(trimethylsiloxy)sylylpropylglycerolethylmethacrylate (“SiGEMA”), and monomethacryloxypropyl functionalpolydimethylsiloxanes such as MCR-M07 and MCS-M11, all available fromGelest (Morrisville, Pa., USA).

In one example, the acrylate-containing siloxane monomer may comprise amonomer represented by formula (I),

where m is an integer from 3 to 10, n is an integer from 0 to 10, R¹ isan alkyl group having 1 to 4 carbon atoms, R² is hydrogen or a methylgroup, and R³ is hydrogen or a methyl group. In a further specificexample, the acrylate-containing siloxane monomer is represented byformula I wherein R¹ is a butyl group, R² is hydrogen, R³ is a methylgroup, m is 4, and n is 1. This particular siloxane monomer isdesignated “Si-1” in the Examples section below. Methods of makingsiloxane monomers represented by formula (I) are described in U.S. Publ.no. 20090299022, incorporated herein by reference.

Another exemplary acrylate-containing siloxane monomer is represented byformula (II),

wherein R₁ is selected from either hydrogen or a methyl group; R₂ isselected from either hydrogen or a C₁₋₄ hydrocarbon group; m representsan integer of from 0 to 10; n represents an integer of from 4 up toabout 15, 25, or 100; a and b represent integers of 1 or more; a+b isequal to 20-500; b/(a+) is equal to 0.01-0.22; and the configuration ofsiloxane units includes a random configuration. In a more specificexample, the acrylate-containing siloxane monomer is represented byformula II wherein R₁ and R₂ are methyl groups, m is 0, n represents aninteger from about 5 to about 10, a represents an integer of from about70 to about 90, and b represent an integer of from 1 to about 10; thissiloxane monomer is designated “Si-2” in the Examples section below andhas a molecular weight of about 8,000 to about 10,000. Methods of makingcompounds of formula II are described in U.S. Publication no.2009/0234089, incorporated herein by reference.

Yet another exemplary acrylate-containing siloxane monomer isrepresented by formula (III),

where n is an integer from about 10 to 15. Siloxane monomers of formulaIII and other suitable monomers are described in U.S. Pat. No. 6,867,245and U.S. Pat. No. 6,310,169, both incorporated herein by reference.

Other suitable acrylate-containing siloxane monomers are represented byformula (IV):

wherein R³ is selected from either hydrogen or a methyl group, mrepresents an integer from 0 to 10, and n represents an integer from 1to 500. In a specific example, the acrylate-containing siloxane monomeris a methacryloxypropyl-terminated polydimethylsiloxane represented byformula III where R³ is a methyl group, m is 0, and n is an integer from40 to 60. This monomer is available from Gelest (Morrisville, Pa., USA)and is referred to as “DMS-R18” from the manufacturer and as “Si-3” inthe Examples below. Additional suitable methacryloxypropyl-terminatedpolydimethylsiloxanes include DMS-R22 and DMS-R31, also available fromGelest.

Yet another suitable acrylate-containing siloxane monomer is representedby formula (V),

wherein n is an integer of about 100 to 150, m and p are both integersof about 5 to 10, and h is an integer of about 2 to 8. Methods of makingcompounds of formula V are described in U.S. Pat. No. 6,867,245,incorporated herein by reference. Additional acrylate-containingsiloxane monomers that can be used in the polymerizable compositiondescribed herein are known in the field (see e.g. U.S. Pat. No.7,572,841, U.S. Publ. No. 2006/0063852, and U.S. Pat. No. 5,998,498,each incorporated herein by reference).

In one example, the acrylate-containing siloxane monomer may comprise acombination of a mono-functional acrylate-containing siloxane monomerand a bi-functional acrylate-containing siloxane monomer. In thisexample, the bi-functional acrylate-containing siloxane monomer may bepresent in the polymerizable composition in amounts of from about 0.04,0.06, 0.08, or 0.10 mol. % and up to about 0.20, 0.25, 0.30, or 0.35mol. %; and the mono-functional acrylate-containing siloxane monomer maybe present in amounts of from about 2, 3, 4 or 5 mol. % up to about 8,10, 12, 15, or 18 mol. %. In one such example, the mono-functionalacrylate-containing siloxane monomer has a molecular weight of less than2,000, 1,500, 1,000, or 750, and the bi-functional acrylate-containingsiloxane monomer has a molecular weight of at least 3,000, 3,500, 4,000,4,500, 5,000, 6,000, 7,000, or 8,000. In the case of polyorganosiloxaneprepolymers, such as those represented by Formulas III, IV, and V above,and other polydisperse monomers, the term “molecular weight” as usedherein, refers to the absolute number average molecular weight (in unitsof Daltons) of the monomer as determined by ¹H NMR end-group analysis.In a specific example, the mono-functional acrylate-containing siloxanemonomer has a molecular weight of from about 250 to about 1000, and thebi-functional acrylate-containing siloxane monomer has a molecularweight of from about 5,000 to about 16,000. In a further specificexample, the mono-functional acrylate-containing siloxane monomer has amolecular weight of from about 500 to about 1000, and the bi-functionalacrylate-containing siloxane monomer has a molecular weight of fromabout 5,000 to about 12,000.

In the above-described example wherein the acrylate-containing siloxanemonomer comprises a combination of a mono-functional acrylate-containingsiloxane monomer and a bi-functional acrylate-containing siloxanemonomer, the mono-functional acrylate-containing siloxane monomer andbi-functional acrylate-containing siloxane monomer may be present in thepolymerizable composition at a molar ratio of at least 20:1, 30:1, 40:1,50:1, 75:1 or 100:1, and optionally up to about 150:1, 175:1, 200:1,225:1 or 250:1, respectively. In a specific example, the molar ratio ofthe mono-functional acrylate-containing siloxane monomer tobi-functional acrylate-containing siloxane monomer is from 30:1 up to150:1, wherein the mono-functional acrylate-containing siloxane monomerhas a molecular weight of from about 500 to about 1000, and thebi-functional acrylate-containing siloxane monomer has a molecularweight of from about 5,000 to about 12,000.

In one example, the polymerizable composition may further comprise anon-siloxane acrylate-containing monomer to further enhance mechanicalstrength and/or stiffness of the lens, or confer other desiredproperties. When present, the total amount of non-siloxaneacrylate-containing monomer in the polymerizable composition istypically from about 12, 14, 16, or 18 mol. % and up to about 20, 25, or30 mol. %. In a specific example, the non-siloxane acrylate-containingmonomer has a polymerizable methacrylate group. Numerous suitablenon-siloxane acrylate-containing monomers are known in the field.Exemplary acrylate-containing monomers include methyl methacrylate(MMA), 2-hydroxybutyl methacrylate (HOB), tert butyl methacrylate(tBMA), N,N-dimethylacrylamide (DMA), 2-hydroxyethyl methacrylate(HEMA), ethoxyethyl methacrylamide (EOEMA), ethylene glycol methyl ethermethacrylate (EGMA), isobornyl methacrylate (IBM), and combinationsthereof.

In one example, the polymerizable composition may additionally comprisean acrylate-containing cross-linking agent. When present, the totalamount of acrylate-containing cross-linking agent in the polymerizablecomposition is typically from about 0.20, 0.25, 0.30, or 0.35 mol. % upto about 0.50, 0.60, 0.70, 0.80, or 1.0 mol. %. In one such example, thetotal amount of acrylate-containing cross-linking agent and the totalamount of vinyl-containing cross-linking agent are at a molar ratio ofat least 3:2, 2:1, 3:1, or 4:1, and optionally up to about 16:1, 14:1,12:1, or 10:1, respectively. In certain examples the acrylate-containingcross-linking agent is free of siloxane moieties, i.e. it is anon-siloxane cross-linking agent. Examples of acrylate-containingcross-linking agents that can be used in the polymerizable compositionsdisclosed herein, include, without limitation, lower alkylene glycoldi(meth)acrylate, poly(lower alkylene) glycol di(meth)acrylate, loweralkylene di(meth)acrylate, trimethylolpropane tri(meth)acrylate,pentaerythritol tetra(meth)acrylate, bisphenol A di(meth)acrylate,methylenebis(meth)acrylamide, and1,3-Bis(3-methacryloxypropyl)tetramethyldisiloxane. In a specificexample, the vinyl-containing cross-linking agent is a divinyl ethersuch as triethyleneglycol divinyl ether (TEGDVE) or diethyleneglycoldivinyl ether (DEGDVE), and the acrylate-containing cross-linking agentis a lower alkylene glycol dimethacrylate such as triethylene glycoldimethacrylate (TEGDMA) or ethylene glycol dimethacrylate (EDGMA). Inother examples, there is no non-siloxane acrylate-containingcross-linking agent in the polymerizable composition, and the presenceof a bi-functional acrylate-containing siloxane monomer in thepolymerizable composition provides an acrylate cross-linking function.In exemplary polymerizable compositions, the total amount of allcross-linkable ingredients in the polymerizable composition (i.e. anyreactive ingredient having more than one polymerizable group, such as abi-functional siloxane, a vinyl-containing cross-linking agent, etc.) isfrom about 0.2, 0.4, or 0.6 mol. % up to about 0.8, 1.0, 1.2, or 1.5mol. %.

The polymerizable compositions can also be described in terms of thepercentage by weight (wt. %) of each reactive component in thepolymerizable composition, and wt. % ratios of various reactivecomponents, wherein the weight percentages are based on total weight ofreactive components of the composition relative to the total weight ofall reactive components. For example, the polymerizable composition mayhave a total amount of acrylate-containing siloxane monomer of fromabout 20 wt. % or 30 wt. % up to about 50 wt. % or 60 wt. %; a totalamount of hydrophilic vinyl-containing monomer of from about 30 wt. %,or 40 wt. % up to about 50 wt. % or 60 wt. %; and a total amount ofvinyl-containing cross-linking agent of from about 0.02 wt. % or 0.05wt. % up to about 0.5 wt. % or 1.0 wt. %. The polymerizable compositionmay additionally have a total amount of an acrylate-containingcross-linking agent of from about 0.05 wt. % to about 4 wt. %. In oneexample, the polymerizable composition may further comprise from about 5wt. % or 10 wt. % up to about 20 wt. % or 25 wt. % of anacrylate-containing monomer. In a further specific example, theacrylate-containing siloxane monomer component of the polymerizablecomposition comprises a combination of at least one mono-functionalacrylate-containing siloxane monomer having a molecular weight of lessthan 2,000, and at least one bi-functional acrylate-containing siloxanemonomer having a molecular weight of at least 3,000 at a wt. % ratio ofat least 2:1, respectively, wherein the total amount of the mono- andbi-functional acrylate-containing siloxane monomers comprise about 25 to50 wt. %, or 30 to 45 wt. % of the composition. These wt. % examples ofthe polymerizable composition may be combined with any of theabove-described molar ratio and/or molar percentage examples.

Polymerizable compositions described herein result in contact lensesthat have ophthalmically acceptably wettable lens surfaces without theinclusion of a high molecular weight hydrophilic polymer (i.e. apreformed polymer) in the polymerizable composition. In a particularexample, the polymerizable composition is substantially free of ahydrophilic polymer. As used herein, “substantially free” means none oran inconsequential amount, i.e. an amount that has no measurable affecton the physical properties of the lens. However, such hydrophilicpolymers may be included in the polymerizable composition, if desired.Examples of such hydrophilic polymers include polyamides, polylactams(especially polyvinylpyrrolidone), polyimides, polylactones, andpolydextrans, having molecular weights of at least 50,000, and aredescribed in U.S. Pat. No. 6,367,929, incorporated herein by reference.Accordingly, in another example the polymerizable compositionadditionally comprises a hydrophilic polymer in an amount that increasesthe wettability of the contact lens relative to a contact lens thatlacks the hydrophilic polymer but is otherwise identical.

As will be appreciated by those skilled in the art, the polymerizablecomposition will typically comprise non-polymerizable ingredients, inaddition to the polymerizable ingredients, that are conventionally usedin contact lens formulations. For example, the polymerizable compositionwill typically include a polymerization initiator, a UV absorbing agent,and a tinting agent. Additional ingredients may also be included such asan organic diluent, an oxygen scavenger, or a chain transfer agent.Non-limiting examples of these and additional ingredients that may beincluded in the polymerizable composition are provided in U.S.Publication No. 2007/0296914, and below.

Contact lenses can be made from the polymerizable compositions describedherein using curing and other processing methods known in the field,such as cast molding, spin casting, injection molding, forming apolymerized rod that is subsequently lathed, etc. In a specific example,the polymerizable composition is cast molded between molds formed of athermoplastic polymer. The thermoplastic polymer is typically anon-polar material, such as polypropylene, but polar mold materials arealso used in the field. Briefly, a first mold member defining the frontsurface of the contact lens, referred to as a “female mold member”, isfilled with an amount of the polymerizable composition sufficient toform a single polymeric lens body. A second mold member defining theback (i.e. eye-contacting) surface of the contact lens, referred to asthe “male mold member”, is coupled to the female mold member to form amold assembly having a lens-shaped cavity with the amount ofpolymerizable composition therebetween.

The polymerizable composition within the contact lens mold assembly ispolymerized using any suitable curing method. Typically, thepolymerizable composition is exposed to polymerizing amounts of heat orultraviolet light (UV). In the case of UV-curing, also referred to asphotopolymerization, the polymerizable composition typically comprises aphotoinitiator such as benzoin methyl ether, 1-hydroxycyclohexylphenylketone, Darocur or Irgacur (available from Ciba Specialty Chemicals).Photopolymerization methods for contact lenses are described in U.S.Pat. No. 5,760,100. In the case of heat-curing, also referred to asthermal curing, the polymerizable composition typically comprises athermal initiator. Exemplary thermal initiators include2,2′-azobis(2,4-dimethylpentanenitrile) (VAZO-52),2,2′-Azobis(2-methylpropanenitrile) (VAZO-64), and 1,1-azobis(cyanocyclohexane) (VAZO-88). In an exemplary thermal curing methodthat can be used to polymerize polymerizable compositions describedherein, the mold assemblies are subjected to a first curing temperatureof from about 50 to 65° C., which is maintained for about 15 to 45minutes, and then the temperature is increased to a second temperatureof at least about 70° C. In one such example, the second curingtemperature can be from about 70 to 85° C. and can be maintained forabout 15 to 45 minutes, then the temperature can be increased again toat least about 90° C., and can be maintained until polymerization issubstantially complete, typically at least about 15 minutes. Additionalthermal polymerization methods for contact lenses are described in U.S.Publ. No. 2007/0296914 and U.S. Pat. No. 7,854,866, incorporated hereinby reference.

In a specific example, during the polymerizing step, less than 50% ofpolymerizable vinyl groups from the polymerizable composition havepolymerized by the time 80% of polymerizable acrylate groups from thepolymerizable composition have polymerized. In a further example, lessthan 50% of polymerizable vinyl groups from the polymerizablecomposition have polymerized by the time 95% of polymerizable acrylategroups from the polymerizable composition have polymerized. A curingsystem with Fourier-transform infrared (FT-IR) and near-infrared (NIR)spectroscopy monitoring capability can be used to monitor the extent ofconversion (i.e. polymerization) of the polymerizable vinyl groups andpolymerizable acrylate groups of a polymerizable composition.

At the completion of curing, the polymerized material between the moldmembers of the mold assembly has the shape of a contact lens, and isreferred to herein as a “polymeric lens body”. The male and female moldmembers are demolded, i.e. separated, and the polymeric lens body isremoved, i.e. delensed, from the mold member to which it is adhered.These processes are referred to as demolding and delensing,respectively, and a variety of such methods are known to those ofordinary skill in the field. In some methods, the demolding anddelensing processes can comprise a single process step, such as when themolds are separated using a liquid which also removes the polymeric lensbody from the mold. In other methods, such as when a dry-demoldingprocess is used, the polymeric lens body typically remains on one of themold members and is delensed in a subsequent process step. Delensing canalso be a wet or dry process. In one example, delensing is carried outby a “float off” method in which the mold member to which a polymericlens body is adhered is immersed in water. The water may optionally beheated (e.g. up to about 100° C.). Typically, the polymeric lens bodiesfloat off of the mold members in about ten minutes. Dry delensing can becarried out manually, for example using tweezers to remove the polymericlens bodies from the mold member, or they can be removed using anautomated mechanical process, such as described in U.S. Pat. No.7,811,483. Additional demolding and delensing methods for siliconehydrogel contact lenses are described in U.S. Publ No. 2007/0035049.

After delensing, the polymeric lens body is washed to remove unreactedor partially reacted ingredients from the polymeric lens body and tohydrate the polymeric lens body. In a specific example, the polymericlens body is washed in a washing liquid free of volatile organicsolvents (e.g. methanol, ethanol, chloroform, etc.), and all liquidsused to wash the polymeric lens body are free of volatile organicsolvents. This type of washing may also be referred to herein as“organic solvent-free extraction” where “organic solvent” refers tovolatile organic solvents. For example, a washing step that uses aqueoussolutions of surfactants such as Tween 80, without any volatile organicsolvents, is considered to be a volatile organic solvent-freeextraction. In a further example, the polymeric lens body is notcontacted by any volatile organic solvents during the manufacturingprocess (i.e. from the time curing of the polymeric lens body iscomplete until the time it is sealed in its final packaging). While thepolymerizable compositions described herein can be used to makepolymeric lenses bodies that can be washed without the use of volatileorganic solvents, if desired, they can also be washed with organicsolvents. Thus, washing steps can include contacting the polymeric lensbody with a volatile organic solvent, such as a lower alcohol (e.g.methanol, ethanol, etc.), contacting the polymeric lens body withaqueous liquids that may or may not contain a volatile organic solvents,solutes, or combinations thereof. Exemplary washing methods aredescribed in U.S. Pat Publ No. 2007/0296914 and in Example 1 below.

The good wettability of the contact lenses achieved from thepolymerizable compositions described herein avoids the need forpost-polymerization surface modification of the polymeric lens body toimpart wettability. One example of a post-polymerization surfacemodification used to impart wettability is surface plasma treatment (seee.g. U.S. Pat. No. 4,143,949). Another example of a post-polymerizationmodification to impart wettability is the coating of hydrophilicpolymers onto the surface of the polymeric lens body such as by alayer-by-layer technique (see e.g. U.S. Pat. No. 7,582,327), or by theaddition of a hydrophilic polymer into the packaging solution (see e.g.U.S. Pat. No. 7,841,716). Accordingly, in a specific example, the methodof making the contact lens is free of a post-polymerization surfacemodification. For example, the method may not include a plasma surfacemodification of the polymeric lens body and/or a hydrophilic polymer maynot be coated onto the polymeric lens body and/or a hydrophilic polymermay not be added to the packaging solution that is placed into thecontact lens package.

After washing, and any optional surface modifications, the hydratedpolymeric lens body is typically placed into a blister package, glassvial, or other appropriate container, all referred to herein as“packages.” A packaging solution is also added to the container, whichis typically a buffered saline solution such as phosphate- orborate-buffered saline. The packaging solution may optionally containadditional ingredients such as a comfort agent, a hydrophilic polymer, asurfactant or other additive that prevents the polymeric lens body fromsticking to the container, etc. The package is sealed, and the sealedpolymeric lens body is sterilized by sterilizing amounts of radiation,including heat or steam, such as by autoclaving, gamma radiation, e-beamradiation, ultraviolet radiation, etc. The final product is a sterile,packaged ophthalmically-acceptable contact lens.

Typically, contact lenses that have been processed using organicsolvent-free extraction will have a “wet extractable component”. Inspecific examples, the wet extractable component of the final contactlens product constitutes about 2 to about 8% of the dry weight of thelens, and usually about 3 to about 6% of the dry weight of the contactlens. The percentage of the wet extractable component in a contact lensis determined using a Sohxlet extraction process as follows: Fivefully-hydrated, sterilized contact lenses from a single lot are removedfrom their packages and excess packaging solution is removed from thelenses with a paper towel. The lenses are dried overnight in an 80° C.vacuum oven, then each dried lens is weighed to get the dry weight ofthe lens (W1). Each lens is then placed in a perforated, stackableTeflon thimble, and the thimbles are stacked to form an extractioncolumn with an empty thimble placed at the top of the column. Theextraction column is placed into a small Sohxlet extractor (VWR80068-164) and the extractor is attached to a condenser (VWR 80068-1580)and a 125 ml round bottom flask (VWR-80068-704) containing about 70-80ml methanol. Water is circulated around the condenser and the methanolis heated until it gently bubbles. The lenses are extracted for 4 hoursfrom the time condensed methanol first begins to drop. Themethanol-extracted lenses are removed from the thimbles and driedovernight at 80° C. in a vacuum oven. Each lens is weighed to obtain thedry weight of the extracted lens (W2), and the following calculation ismade for each lens: [(W1-W2)/W1]*100. The average of the five values istaken to be the percentage of wet extractable for each lens of the lotof lenses tested.

The contact lenses described herein are “ophthalmically-acceptable”meaning that the lenses have ophthalmically acceptably wettable lenssurfaces and ionoflux values such that the lenses typically do not causeor are not associated with significant corneal swelling, cornealdehydration (“dry eye”), superior epithelial arcuate lesions (“SEALs”),or other significant discomfort. Determining whether a contact lens isophthalmically acceptable can be achieved using conventional clinicalmethods, such as those performed by an eye care practitioner, and asunderstood by persons of ordinary skill in the art.

In any of the above-described examples, the contact lens may becharacterized by one or more of the following properties: ionoflux,contact angle, oxygen permeability, tensile modulus, equilibrium watercontent, and % energy loss, as detailed in the following sevenparagraphs.

In any of the above-described examples, the contact lens may have anionoflux of less than about 10×10⁻³ mm²/min, 9×10⁻³ mm²/min, 8×10⁻³mm²/min, 7×10⁻³ mm²/min, 6×10⁻³ mm²/min, 5×10⁻³ mm²/min, or 4×10⁻³mm²/min as measured using the “Ionoflux Technique” described in U.S.Pat. No. 5,849,811, incorporated by reference herein, or an equivalentmethod such as the following method that was used to determine theionoflux values provided in the Examples below. A hydrated lens isplaced in 40 ml deionized water for 10 minutes. The lens is then placedin a lens-retaining device, between male and female portions. The maleand female portions include flexible sealing rings which are positionedbetween the lens and the respective male or female portion. Thelens-retaining device is then placed in a threaded lid. The lid isscrewed onto a glass tube to define a donor chamber. The donor chamberis filled with 16 ml of 0.1 molar NaCl solution. A 100 ml beaker, usedas a receiving chamber, is filled with 80 ml of deionized water. Leadsof a conductivity meter and a stir bar are immersed in the deionizedwater of the receiving chamber. The receiving chamber is placed in a 250ml beaker jacket that was filled with about 50 ml deionized water andconnected to a water bath with temperature control set to achieve atemperature of about 35° C. in the receiving chamber. Finally, the donorchamber is immersed in the receiving chamber so that the NaCl solutioninside the donor chamber is level with the water inside the receivingchamber. Once the temperature inside the receiving chamber reaches 35°C., conductivity is recorded for 10 minutes. The conductivity versustime data in each of the examples below was substantially linear.

In any of the above-described examples, the contact lens may have acontact angle of less than about 80°, 70°, or 60°, where the contactangle is the dynamic advancing contact angle as determined using acaptive bubble method using a DSA 100 Drop Shape Analysis System fromKrüss as described in Maldonado-Codina, C. and Morgan, P. B. (2007), Invitro water wettability of silicone hydrogel contact lenses determinedusing the sessile drop and captive bubble techniques. Journal ofBiomedical Materials Research Part A, 83A: 496-502.

In any of the above-described examples, the oxygen permeability of thecontact lens (Dk) may be at least 55 barrers, or at least 60 barrers. Dkvalues can be determined using standard methods in the industry, such asby using an Ox-Tran model oxygen transmission rate test system availablefrom Mocon, Inc (Minneapolis, Minn.). The Dk values provided in theExamples below were determined using the method described by Chhabra etal. (2007), A single-lens polarographic measurement of oxygenpermeability (Dk) for hypertransmissible soft contact lenses.Biomaterials 28: 4331-4342.

In any of the above described examples, the contact lens may have atensile modulus (i.e. Young's modulus) of about 0.2 MPa, 0.3 MPa, or 0.4MPa, up to about 0.7 MPa, 0.8 MPa, or 0.9 MPa as measured by an ANSIZ80.20 standard using an Instron Model 3342 or Model 3343 mechanicaltesting system, or equivalent method. The modulus, elongation, andtensile strength values reported herein were determined using an InstronModel 3342 or 3343 mechanical testing system (Instron Corporation,Norwood, Mass., USA) and Bluehill Materials Testing Software, using acustom built rectangular contact lens cutting die with 4 mm spacing toprepare the rectangular sample strip. The modulus was determined insidea chamber having a relative humidity of least 70%. A lens was soaked inphosphate buffered solution (PBS) for at least 10 minutes prior totesting. While holding the lens concave side up, a central strip of thelens was cut using the cutting die. The thickness of the strip wasdetermined using a calibrated gauge (Rehder electronic thickness gauge,Rehder Development Company, Castro Valley, Calif., USA). Using tweezers,the strip was loaded into the grips of the calibrated Instron apparatus,with the strip fitting over at least 75% of the grip surface of eachgrip. A test method designed to determine the maximum load (N), thetensile strength (MPa), the strain at maximum load (% elongation) andthe mean and standard deviation of the tensile modulus (MPa) was run,and the results were recorded.

In any of the above-described examples, the contact lens may have anequilibrium water content (EWC) of greater than about 30 wt. %, 40 wt. %or 50 wt. % and up to about 60 wt. % or 70 wt. %. To measure EWC, excesssurface water is wiped off of the lens and the lens is weighed to obtainthe hydrated weight. The lens is dried in an oven at 80° C. under avacuum, and weighed. The weight difference is determined by subtractingthe weight of the dry lens from the weight of the hydrated lens. The wt.% EWC of the lens is =(weight difference/hydrated weight)×100. In aspecific example, the contact angle is ≦70° and the equilibrium watercontent is at least about 40 wt. %.

The contact lenses described herein are considered “dimensionallystable” if they are from a batch (i.e. lot) of contact lenses thatexhibit an average dimensional stability variance of ≦±3.0% (i.e. lessthan or equal to plus or minus three percent) as determined by thefollowing method. The chord diameters of twenty lenses from a single lotare measured, and the average “original” diameter is obtained.Concurrently, twenty unopened packages of lenses from the same lot areplaced in an incubator set at 55° C. The lenses are kept at thiselevated temperature storage condition for three months to approximate atwo-year shelf life at 25° C. At the end of three months the packagedlenses are brought to room temperature, removed from their packaging,and measured to obtain the average “final” diameter. The dimensionalstability variance is calculated by the equation: (Diameter_(Final)-Diameter _(original)/Diameter _(original))×100. In someexamples, the dimensional stability variance is ≦±2.5% or ≦±2.0%. Inother examples, the lenses have a dimensional stability variance of≦±3.0% as determined using the above-described method except that theincubator is set at 65° C. This elevated temperature storage conditionis considered to approximate a four-year shelf life at 25° C.

In any of the above described examples, the contact lens may have apercent energy loss of at least about 25, 27, or 30 up to about 37, 40,or 45 as determined using a test method in accordance with ANSI Z80.20.The energy loss values reported herein were determined using an InstronModel 3343 (Instron Corporation, Norwood, Mass., USA) mechanical testingsystem, with a 10N force transducer (Instron model no. 2519-101) andBluehill Materials Testing Software including a TestProfiler module.Briefly, the energy loss was determined inside a chamber having arelative humidity of least 70%. A lens was soaked in phosphate bufferedsolution (PBS) for at least 10 minutes prior to testing. Using tweezers,the lens was loaded into the grips of the calibrated Instron apparatus,with the lens loaded vertically between the grips as symmetrically aspossible and fitting over at least 75% of the grip surface of each grip.A test designed to determine the energy required to stretch the lens to100% strain and then return it to 0% strain at a rate of 50 mm/minutewas then run on the lens. The test was conducted only once on a singlelens. Once the test was finished energy loss was calculated: Lost Energy(%)=(Energy to 100% strain-Energy to return to 0% strain)/Energy to 100%strain×100%.

As is evident from the disclosure of the application as a whole,including the claim structure and the specific examples, the exemplarycomponents of the polymerizable composition disclosed herein aretypically combined in embodiments of the invention. For example, theperson skilled in the art would recognise that the polymerizablecomposition of the invention advantageously includes the exemplaryacrylate-containing siloxane monomers disclosed herein in combinationwith the exemplary hydrophilic vinyl-containing monomers disclosedherein and/or in combination with the exemplary vinyl-containingcross-linking agents disclosed herein.

Thus, the acrylate-containing siloxane monomers disclosed above arepresent in the polymerizable compositions of the invention incombination with any of the hydrophilic vinyl-containing monomersdisclosed above, or combinations of hydrophilic vinyl-containingmonomers disclosed above. For example, the acrylate-containing siloxanemonomers of formula (I) may optionally be used in combination with anyone of the hydrophilic vinyl-containing monomers disclosed above,especially in combination with VMA, NVP, BVE, EGVE, or DEGVE.

Similarly, the acrylate-containing siloxane monomers disclosed above arepresent in the polymerizable compositions of the invention incombination with any of the vinyl-containing cross-linking agentsdisclosed above. For example, the acrylate-containing siloxane monomersof formula (I) may optionally be used in combination with any one of thevinyl-containing cross-linking agents disclosed above, especially incombination with TEGDVE or DEGDVE.

Similarly, the hydrophilic vinyl-containing monomers disclosed above, orcombinations of hydrophilic vinyl-containing monomers disclosed aboveare, advantageously, present in the polymerizable compositions of theinvention in combination with any of the vinyl-containing cross-linkingagents disclosed above. For example, VMA, NVP, BVE, EGVE, or DEGVE mayoptionally be used in combination with any of the vinyl-containingcross-linking agents disclosed above, especially in combination withTEGDVE or DEGDVE.

Furthermore, the acrylate-containing siloxane monomers disclosed aboveare, advantageously, present in the polymerizable compositions of theinvention in combination with any of the hydrophilic vinyl-containingmonomers disclosed above, or combinations of hydrophilicvinyl-containing monomers disclosed above, and any of thevinyl-containing cross-linking agents disclosed above. Thus, thepolymerizable compositions of the invention may optionally include acombination of one or more of the acrylate-containing siloxane monomersof formula (I), together with both (i) a hydrophilic vinyl-containingmonomer (such as VMA, NVP, BVE, EGVE, or DEGVE) and (ii) avinyl-containing cross-linking agent (such as TEGDVE or DEGDVE).

As demonstrated by the specific examples, it has been found that acombinations of the preferred acrylate-containing siloxane monomers,hydrophilic vinyl-containing monomers, and/or vinyl-containingcross-linking agents of the invention provide contact lenses of theinvention with low ionoflux and/or other advantageous properties.

EXAMPLES

The following Examples illustrate certain aspects and advantages of thepresent invention, which should be understood not to be limited thereby.Example 1 describes contact lens processing methods, and Examples 2-12show exemplary polymerizable compositions that were used to make contactlenses using the methods described in Example 1. The polymerizablecompositions had good processability resulting in defect- anddistortion-free contact lenses. The contact lenses produced wereoptically clear, meaning that light transmittance between 381 nm to 780nm was at least 97% (measured in accordance with ISO 18369). Additionalphysical properties of the lenses are provided in the examples below.Table 1 shows the abbreviation used for each ingredient as well as itsmolecular weight, which was used to calculate the molar ratios shown ineach example. The molar ratios were determined by dividing the unitamount of an ingredient by its molecular weight to obtain the relativemolar amount of the ingredient in the polymerizable composition, andcomparing that value to the molar amount of another ingredient in thecomposition. The molar ratios compared are designated A-C in eachexample as follows: A. hydrophilic vinyl-containing monomer toacrylate-containing siloxane monomer; B. monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer; and C. vinyl amide-containing monomer to vinylether-containing monomer. Additionally, the ratio of polymerizable vinylgroups from the hydrophilic vinyl-containing monomers (i.e. one permolecule) respective to the polymerizable vinyl groups from thevinyl-containing cross-linking agent used, triethyleneglycol divinylether, (i.e. two per molecule) is provided as ratio D. For eachpolymerizable composition, the relative unit parts, based on weight, areshown. Molar percentages (mol. %) and weight percentages (wt. %) foreach reactive ingredient are provided, except that mol. % values of lessthan 0.01 are not provided. The mol. % and wt. % of a given componentare relative to the total moles and weight, respectively, of allreactive components in the composition prior to initiation of curing.

TABLE 1 Abbreviation Compound Molecular Wt Si-1 Formula I above whereinR¹ is a butyl group, R² is 583 hydrogen, R³ is a methyl group, m = 4,and n = 1 Si-2 A compound of formula II above wherein R₁ and R₂ are9,300 methyl groups, m is 0, n represents an integer from about 5 toabout 10, a represents an integer of from about 70 to about 90, and brepresent an integer of from 1 to about 10 Si-3 Methacryloxypropylterminated polydimethylsiloxane 4,500 AE 2-Allyloxy ethanol 102 BVE4-butanediol vinyl ether 116 DEGVE diethylene glycol vinyl ether 132EGDMA ethylene glycol dimethacrylate 198 EGMA ethylene glycol methylether methacrylate 144 EGVE ethylene glycol vinyl ether 88 HEMA2-hydroxyethyl methacrylate 130 HOB 2-hydroxybutyl methacrylate 158 MMAmethyl methacrylate 100 UV22-(3-(2H-benzotriazol-2-YL)-4-hydroxy-phenyl) ethyl 323 methacrylate(CAS no. 96478-0-0) pTPP Diphenyl (P-vinylphenyl)phosphine (CAS no.40538-11-2) 288 RBT1 2-Propenoicacid,2-methyl-,1,1′-[(9,10-dihydro-9,10-dioxo-1,4-anthracenediyl)bis(imino-2,1-ethanediyl)]ester (CAS no.121888-69-5) RBT2 1,4-bis[4-[(2-methacryl-oxyethyl)phenylamino]anthraquinone TEGDMA triethylene glycol dimethacrylate 286 TEGDVEtriethyleneglycol divinyl ether 202 TPP Triphenyl phosphine (CAS no.603-35-0) V-64 2,2′-Azobis-2-methyl propanenitrile VMAN-vinyl-N-methylacetamide 99

Example 1 Silicone Hydrogel Contact Lens Fabrication

The chemical compounds listed in the tables in Examples 2-12 wereweighed and mixed together to form polymerizable compositions. Eachpolymerizable composition was filtered using a 0.2-5.0 micron filter andstored for up to about 2 weeks at 2-10° C. prior to cast molding andcuring.

The polymerizable composition was cast molded by placing a volume of thecomposition on a female mold member and fitting a male mold memberthereon to form a contact lens mold assembly. The female and male moldmembers were made from a non-polar resin (e.g.polypropylene). Thepolymerizable composition was thermally cured to form a polymeric lensbody by placing the mold assembly in a nitrogen oven at the followingcycle: 30 min. N₂ purging at room temperature, 40 min. at 55° or 65° C.,40 min. at 80° C., and 40 min. at 100° C.

After curing, the male and female mold members were dry demolded and thepolymeric lens bodies were dry delensed from the male mold members. Thedelensed lens bodies were then extracted in alcohol, followed byhydration in water (Example 2) or were washed using organic-solvent freeextraction (Examples 3-12). For alcohol extraction, lens trayscontaining the polymeric lens bodies were immersed in ethanol. After aperiod of time the ethanol was exchanged with fresh ethanol. Then thelens bodies were immersed in a solution of 50:50 ethanol/DI water. Aftera period of time, the lens bodies were immersed in a two exchanges of DIwater. For organic solvent-free extraction, lenses were transferred toindividual wells of a washing tray containing DI water and Tween 80(washing solution). After several minutes, the washing solution wasaspirated, and the wells refilled with washing solution; this step wasrepeated 1-2 times. The extracted and hydrated lenses were placed intoblister packages containing a buffered packaging solution, and thepackages were sealed and autoclaved.

Example 2 Formulation 1

The polymerizable composition of Formulation 1 shown in Table 2 was usedto make contact lenses using the methods described in Example 1, inwhich alcohol extraction was used. The composition had the followingapproximate molar ratios: A=9:1, B=48:1, C=n/a, and D=504:1.

TABLE 2 Abbreviation Unit Amount Mol. % Wt. % Si-1 30 6.8 26.5 Si-2 100.14 8.8 VMA 48 63.9 42.3 EGMA 7 6.4 6.2 MMA 15 19.8 13.2 EGDMA 0.5 0.330.44 TEGDVE 0.1 0.07 0.09 AE 1.4 1.8 1.2 V-64 0.5 0.40 0.44 UV2 0.9 0.370.79 RBT2 0.01 0.01 TPP 0.5

Silicon hydrogel contact lenses made from this formulation hadacceptable dimensional stability, an oxygen permeability of greater than60 barrers, an EWC of about 53%, a modulus of about 0.40 MPa, a tensilestrength of about 1.4 MPa, a dynamic captive bubble advancing contactangle of about 48 to 52 degrees, a light transmittance of about 98%, awet extractable component of about 1.30%, an ionoflux of about 2.9×10⁻³mm²/min, and an energy loss from about 35 to 36%.

Example 3 Formulation 2

The polymerizable composition designated Formulation 2 shown in Table 3was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=9:1, B=62:1, C=17:1, and D=244:1.

TABLE 3 Abbreviation Unit Amount Mol. % Wt. % Si-1 32 7.9 30.9 Si-3 40.13 3.9 VMA 45 64.0 43.5 MMA 13 18.6 12.6 EGMA 3 3.0 2.9 BVE 3 3.7 2.9TEGDMA 1 0.50 0.97 TEGDVE 0.2 0.14 0.19 pTPP 0.5 0.25 0.48 V-64 0.5 0.430.48 RBT1 0.01 0.01 UV2 1.3 0.40 1.3

Silicone hydrogel contact lenses made from this formulation had an EWCof about 57%, a modulus of about 0.70 MPa, an energy loss of about 40%,and a captive bubble dynamic advancing contact angle of from about 50 toabout 60 degrees.

Example 4 Formulation 3

The polymerizable composition designated Formulation 3 shown in Table 4was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=10:1, B=41:1, C=7:1, and D=236:1.

TABLE 4 Abbreviation Unit Amount Mol. % Wt. % Si-1 26 6.6 25.1 Si-2 100.16 9.6 VMA 40 59.5 38.6 MMA 12 17.7 11.6 EGMA 5 5.1 4.8 BVE 7 8.9 6.8TEGDMA 1.2 0.62 1.2 TEGDVE 0.2 0.15 0.19 pTPP 0.5 0.28 0.48 Vazo64 0.50.45 0.48 RB 247 0.01 0.01 UV2 1.3 0.59 1.3

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, a modulus of about 0.50 MPa, and a captive bubble dynamicadvancing contact angle of about 47 to about 51 degrees.

Example 5 Formulation 4

The polymerizable composition designated Formulation 4 shown in Table 5was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=9:1, B=41:1, C=16:1, and D=436:1.

TABLE 5 Abbreviation Unit Amount Mol. % Wt. % Si-1 26 7.0 26.3 Si-2 100.17 10.1 VMA 40 62.9 40.4 MMA 12 18.7 12.1 EGMA 5 5.4 5.1 BVE 3 4.0 3.0EGDMA 0.5 0.39 0.51 TEGDVE 0.1 0.08 0.10 pTPP 0.5 0.27 0.51 V-64 0.50.47 1.3 UV2 1.3 0.63 0.01 RBT1 0.01 0.51

Silicone hydrogel contact lenses made from this formulation had an EWCof about 55%, a modulus of about 0.60 MPa, and a captive bubble dynamicadvancing contact angle of from about 47 to about 55 degrees.

Example 6 Formulation 5

The polymerizable composition designated Formulation 5 shown in Table 6was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=10:1, B=56:1, C=8:1, and D=301:1.

TABLE 6 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.1 28.3 Si-2 80.12 7.8 VMA 44 63.3 42.9 MMA 14 19.9 13.7 EGVE 5 8.1 4.9 EGDMA 0.6 0.430.59 TEGDVE 0.15 0.11 0.15 V-64 0.5 0.43 0.49 UV2 1.3 0.57 1.3 RBT1 0.010.01

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, and a modulus of about 0.65 MPa.

Example 7 Formulation 6

The polymerizable composition designated Formulation 6 shown in Table 7was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=9:1, B=58:1, C=n/a, and D=464:1.

TABLE 7 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.3 28.3 Si-2 80.13 7.8 VMA 45 66.7 43.9 MMA 13 19.1 12.7 HEMA 4 4.5 3.9 EGDMA 0.5 0.370.49 TEGDVE 0.1 0.07 0.10 pTPP 0.5 0.25 0.49 AE 0.3 0.43 1.7 V-64 0.50.45 0.01 UV2 1.7 0.77 0.49 RBT1 0.01 0.29

Silicone hydrogel contact lenses made from this formulation had an EWCof from about 55% to about 56%, a modulus of about 0.53 MPa, a captivebubble dynamic advancing contact angle of from about 51 to about 53degrees, and an energy loss of about 34%.

Example 8 Formulation 7

The polymerizable composition designated Formulation 7 shown in Table 8was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=10:1, B=58:1, C=8:1, and D=488:1.

TABLE 8 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.5 27.9 Si-2 80.13 7.7 VMA 42 63.6 40.5 MMA 8 12.0 7.7 EGMA 6 6.3 5.8 DEGVE 7 8.0 6.7EGDMA 0.6 0.45 0.58 TEGDVE 0.1 0.07 0.10 pTPP 0.5 0.26 0.48 AE 0.4 0.590.39 V-64 0.5 0.46 0.48 UV2 1.7 0.79 1.6 RBT1 0.01 0.01

Silicone hydrogel contact lenses made from this formulation had an EWCof from 57% to 58%, a modulus of about 0.7 MPa, a tensile strength ofabout 1.5 MPa, a captive bubble dynamic advancing contact angle of fromabout 44 to about 48 degrees, a wet extractable component of about 5.1%,an ionoflux of about 2.9×10⁻³ mm²/min, and an energy loss from about 32%to about 33%.

Example 9 Formulation 8

The polymerizable composition designated Formulation 8 shown in Table 9was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=9:1, B=58:1, C=n/a, and D=464:1.

TABLE 9 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.83 28.3 Si-2 80.14 7.8 VMA 45 71.6 43.9 HOB 7 7.0 6.8 EGMA 10 10.9 9.8 EGDMA 0.5 0.40.49 TEGDVE 0.1 0.08 0.10 pTPP 0.5 0.27 0.49 AE 0.3 0.46 0.29 V-64 0.50.48 0.49 UV2 1.7 0.83 1.7 RBT1 0.01 0.01

Silicone hydrogel contact lenses made from this formulation had an EWCof from about 55% to about 56%, a modulus of about 0.6 MPa, a tensilestrength of about 1.2 MPa, a captive bubble dynamic advancing contactangle of from about 55 to about 58 degrees, a wet extractable componentof about 4.6%, an ionoflux of about 4.1×10⁻³ mm²/min, and an energy lossof from about 31% to about 32%.

Example 10 Formulation 9

The polymerizable composition designated Formulation 9 shown in Table 10was used to make contact lenses using the methods described in Example1, in which all liquids used for washing the polymeric lens body weresubstantially free of volatile organic solvents. The composition had thefollowing approximate molar ratios: A=11:1, B=68:1, C=5:1, and D=752:1.

TABLE 10 Abbreviation Unit Amount Mol. % Wt. % Si-1 30 6.9 26.7 Si-2 70.10 6.2 VMA 44 59.9 39.1 MMA 8 10.8 7.1 EGMA 6 5.6 5.3 DEGVE 10 10.28.9 BVE 4 4.6 3.6 EGDMA 0.6 0.41 0.53 TEGDVE 0.1 0.05 0.09 pTPP 0.5 0.260.44 V-64 0.5 0.41 0.44 RBT1 0.01 0.01 UV2 1.8 0.75 1.6

Silicone hydrogel contact lenses made from this formulation hadacceptable dimensional stability, an EWC of about 61%, a modulus ofabout 0.5 MPa, a tensile strength of about 1.2 MPa, a captive bubbledynamic advancing contact angle of from about 45 to about 47 degrees, awet extractable component of about 4.55%, an ionoflux of about 3.8×10⁻³mm²/min, and an energy loss of from about 30% to about 33%.

Example 11 Formulation 10

The polymerizable composition designated Formulation 10 shown in Table11 was used to make contact lenses using the methods described inExample 1, in which all liquids used for washing the polymeric lens bodywere substantially free of volatile organic solvents. The compositionhad the following approximate molar ratios: A=10:1, B=68:1, C=7:1, andD=252:1.

TABLE 11 Abbreviation Unit Amount Mol. % Wt. % Si-1 30 7.07 27.4 Si-2 70.10 6.4 VMA 45 62.5 41.1 MMA 12 16.5 11.0 EGMA 6 5.7 5.5 BVE 5 5.9 4.6TEGDMA 1.4 0.67 1.3 TEGDVE 0.2 0.14 0.18 pTPP 0.5 0.24 0.46 V-64 0.50.42 0.46 RBT1 0.01 0.01 UV2 1.8 0.76 1.7

Silicone hydrogel contact lenses made from this formulation hadacceptable dimensional stability, an EWC of from about 55% to about 57%,a modulus of about 0.7 MPa, a tensile strength of about 1.3 MPa, acaptive bubble dynamic advancing contact angle of from about 47 to about53 degrees, a wet extractable component of about 4.1%, an ionoflux ofabout 3.6×10⁻³ mm²/min, and an energy loss of from about 34% to about35%.

Example 12 Formula 11

The polymerizable composition designated Formulation 11 shown in Table12 was used to make contact lenses using the methods described inExample 1, in which all liquids used for washing the polymeric lens bodywere substantially free of volatile organic solvents. The compositionhad the following approximate molar ratios: A=10:1, B=41:1, C=7:1, andD=457:1.

TABLE 12 Abbreviation Unit Amount Mol. % Wt. % Si-1 25.2 7.04 25.2 Si-29.7 0.17 9.7 VMA 38.8 63.9 38.8 BVE 6.8 9.6 6.8 EGMA 4.8 5.4 4.8 EOEMA11.6 12.0 11.6 TEGDMA 1.2 0.68 1.2 TEGDVE 0.1 0.08 0.10 V-64 0.5 0.500.50 UV2 0.9 0.45 0.9 RBT1 0.01 0.01 pTPP 0.5 0.28 0.50

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, a modulus of about 0.57 MPa, a tensile strength of about1.90 MPa, a wet extractable component of about 4.74%, and an energy lossof about 34 to 36%.

Although the disclosure herein refers to certain illustrated examples,it is to be understood that these examples are presented by way ofexample and not by way of limitation. The intent of the foregoingdetailed description, although discussing exemplary examples, is to beconstrued to cover all modifications, alternatives, and equivalents ofthe examples as may fall within the spirit and scope of the invention asdefined by the additional disclosure.

A number of publications and patents have been cited hereinabove. Eachof the cited publications and patents are hereby incorporated byreference in their entireties.

What is claimed is:
 1. A silicone hydrogel contact lens comprising: apolymeric lens body that is a reaction product of a polymerizablecomposition comprising a) at least one acrylate-containing siloxanemonomer represented by formula (I):

where m is an integer from 3 to 10, n is an integer from 0 to 10, R¹ isan alkyl group having 1 to 4 carbon atoms, R² is hydrogen or a methylgroup, and R³ is hydrogen or a methyl group; b) at least one hydrophilicvinyl-containing monomer; and c) at least one vinyl-containingcross-linking agent, wherein the contact lens has an ionoflux of lessthan 10×10⁻³ mm²/min; and wherein the polymerizable composition has amolar ratio of total amount of hydrophilic vinyl-containing monomer tototal amount of acrylate-containing siloxane monomer of from 5:1 to30:1, respectively.
 2. The contact lens of claim 1, wherein thepolymerizable composition has a total amount of acrylate-containingsiloxane monomer of from about 2 mol. % to about 15 mol. %.
 3. Thecontact lens of claim 1, wherein the polymerizable composition has atotal amount of hydrophilic vinyl-containing monomer of from about 50mol. % to about 85 mol. %.
 4. The contact lens of claim 1, wherein thepolymerizable composition has a total amount vinyl-containingcross-linking agent of from about 0.02 mol. % to about 0.20 mol. %. 5.The contact lens of claim 1, wherein the at least one hydrophilicvinyl-containing monomer is selected from N-vinyl-N-methyl acetamide(VMA), or N-vinyl pyrrolidone (NVP), or 1,4-butanediol vinyl ether(BVE), or ethylene glycol vinyl ether (EGVE), or diethylene glycol vinylether (DEGVE), or any combination thereof.
 6. The contact lens of claim1, wherein the at least one hydrophilic vinyl-containing monomer isN-vinyl-N-methyl acetamide (VMA).
 7. The contact lens of claim 1,wherein the at least one hydrophilic vinyl-containing monomer comprisesa first hydrophilic vinyl-containing monomer having a firstpolymerizable group and a second hydrophilic vinyl-containing monomerhaving a second polymerizable group that is different from the firstpolymerizable group.
 8. The contact lens of claim 1, wherein the atleast one hydrophilic vinyl-containing monomer comprises at least onehydrophilic vinyl amide-containing monomer and at least one hydrophilicvinyl ether-containing monomer.
 9. The contact lens of claim 8, whereinthe polymerizable composition has a molar ratio of total amount ofhydrophilic vinyl amide-containing monomer to total amount ofhydrophilic vinyl ether-containing monomer of from 2:1 to 30:1,respectively.
 10. The contact lens of claim 8, wherein the polymerizablecomposition has a molar ratio of total amount of hydrophilic vinylamide-containing monomer to total amount of hydrophilic vinylether-containing monomer of from 4:1 to 15:1, respectively.
 11. Thecontact lens of claim 8, wherein the polymerizable composition has atotal amount of vinyl amide-containing monomer of from about 50 to about75 mol. %.
 12. The contact lens of claim 8, wherein the polymerizablecomposition has a total amount vinyl ether-containing monomer of fromabout 2 to about 20 mol. %.
 13. The contact lens of claim 1, wherein theat least one vinyl-containing cross-linking agent is selected fromdivinyl ether, or divinyl sulfone, or triallyl phthalate, or triallylisocyanurate, or diallyl phthalate, or diethyleneglycol divinyl ether,or triethyleneglycol divinyl ether, or any combination thereof.
 14. Thecontact lens of claim 1, wherein the at least one vinyl-containingcross-linking agent is a divinyl ether.
 15. The contact lens of claim 1,further comprising a bi-functional acrylate-containing siloxane monomer.16. The contact lens of claim 15, wherein the bi-functionalacrylate-containing siloxane monomer has a molecular weight of at least3,000.
 17. The contact lens of claim 15, wherein the acrylate-containingsiloxane monomer represented by formula (I) and the bi-functionalacrylate-containing siloxane monomer are present in the polymerizablecomposition at a molar ratio of at least 30:1, respectively.
 18. Thecontact lens of claim 1, wherein the polymerizable composition furthercomprises at least one non-siloxane acrylate-containing monomer.
 19. Thecontact lens of claim 1, wherein the polymerizable composition has atotal amount of cross-linkable ingredients of from about 0.2 to about1.5 mol. %.
 20. The contact lens of claim 1 having an ionoflux of lessthan 8×10⁻³ mm²/min.
 21. The contact lens of claim 1, wherein thepolymerizable composition is substantially free of hydrophilic polymer.22. The contact lens of claim 1 that is free of post-polymerizationsurface modification.
 23. The contact lens of claim 1 characterized byone or more of the following features: a) a dynamic advancing contactangle of less than 70° as determined using a captive bubble method; b)an oxygen permeability of at least 60 barrers; c) a tensile modulus fromabout 0.2 MPa to about 0.9 MPa; d) an equilibrium water content fromabout 30% wt/wt to about 70% wt/wt; e) an energy loss from about 27 toabout 45%; and f) an ionoflux of less than 6×10⁻³ mm²/min.
 24. Thecontact lens of claim 1 having a wet extractable component of about 2 toabout 8% based on dry weight of the contact lens.
 25. The contact lensof claim 1 sterilized in a sealed package.
 26. A method of manufacturingthe silicone hydrogel contact lens of claim 1 comprising: polymerizingthe polymerizable composition to make the polymeric lens body, andwashing the polymeric lens body with a washing liquid to removeunreacted or partially reacted components from the polymeric lens body.27. The method of claim 26, wherein the washing liquid and any otherliquid used for washing the polymeric lens body are substantially freeof volatile organic solvents.
 28. A method of manufacturing a siliconehydrogel contact lens comprising: a) preparing a polymerizablecomposition comprising at least one acrylate-containing siloxane monomerrepresented by formula (I):

where m is an integer from 3 to 10, n is an integer from 0 to 10, R¹ isan alkyl group having 1 to 4 carbon atoms, R² is hydrogen or a methylgroup, and R³ is hydrogen or a methyl group, at least one hydrophilicvinyl-containing monomer, and at least one vinyl-containingcross-linking agent; b) polymerizing the polymerizable composition toform a polymeric lens body; and c) contacting the polymeric lens bodywith a washing liquid to remove unreacted or partially reactedcomponents from the polymeric lens body, wherein the washing liquid andany other liquid used for washing the polymeric lens body aresubstantially free of volatile organic solvents; wherein thepolymerizable composition has a molar ratio of total amount ofhydrophilic vinyl-containing monomer to total amount ofacrylate-containing siloxane monomer of from 5:1 to 30:1, respectively.29. The method of claim 28, further comprising sealing the polymericlens body in a package comprising a packaging solution and sterilizingthe sealed package.
 30. The method of claim 28, wherein the polymerizingoccurs in a mold having non-polar molding surfaces.
 31. The method ofclaim 28, wherein the polymerizing step comprises thermal curing. 32.The method of claim 31, wherein the polymerizing step comprises a firstcuring temperature of about 50 to 65° C. maintained for about 15 to 45minutes, and a second curing temperature of at least about 70° C. 33.The method of claim 32, wherein the second curing temperature is about70 to 85° C. and is maintained for about 15 to 45 minutes, and thethermal curing process further comprises a third curing temperature ofat least about 90° C. maintained for at least about 15 minutes.
 34. Themethod of claim 28 that is free of a post-polymerization surfacemodification step.